Multi-layer optical disc format

ABSTRACT

An optical disc ( 102 ) and method for forming the same. The optical disc preferably includes a first substrate ( 150 ) comprising a pre-recorded, first data storage layer ( 152 ) and a second substrate (156) comprising a recordable, second data storage layer ( 158 ). The second substrate is affixed to the first substrate such that a data transducing beam ( 161 ) passes through a common exterior boundary surface ( 162 ) of the disc to access the respective first and second layers. Preferably, the pre-recorded layer comprises a sequence of pits and lands ( 218 ). Addresses of blocks in the respective layers preferably successively increment ( 220 ) so that a readback system ( 100 ) interprets the respective layers as a common recording layer within the disc. One of the layers can store disc authentication data zone, a patch which updates a version of user data stored in the remaining layer, etc. A content supplier can supply specially configured substrates with pre-recorded control data to control disc manufacture.

FIELD OF THE INVENTION

The present invention relates generally to the field of optical disctechnology and more particularly, but without limitation, to an improvedoptical disc format and a method for forming the same.

BACKGROUND

Optical discs are data storage media used to store a wide variety ofdigitally encoded data. Such discs are usually portable in nature andcan be played in a variety of settings such as personal computers, caraudio players, home theater systems, handheld personal entertainmentdevices, home gaming systems, etc.

A typical optical disc comprises a circular disc having one or more datastorage (recording) layers of light reflective material embedded in arefractive substrate. Each layer is typically disposed along a planesubstantially normal to an axis about which the disc is rotated andstores data in the form of localized areas of different reflectivity(pits and lands). The data can be stored along a continuously extendingspiral track or a number of nested concentric tracks.

A data transducing head uses a laser or similar light source to output areadback signal based on the different reflectivities of the pit andland areas. Decoding circuitry decodes the user data for output by theappropriate playback device.

Optical discs can be pre-recorded or recordable. A pre-recorded disctypically includes an embedded metallized layer that stores therespective pits and lands. The metallized layer is formed duringmanufacturing of the disc using an injection molding process, and thedata are permanently embossed in the disc once the disc manufacturingoperation is completed.

Recordable discs are media to which data can be written. As used herein,“recordable” covers both discs that can be written once (WORM discs) orwritten and erased many times (rewritable discs). WORM discs typicallyutilize an embedded layer of dye or other material that can beselectively exposed to a write laser beam to permanently provide areasof different reflectivities corresponding to the pits and lands.Rewritable discs typically utilize a light beam to write the data as aseries of areas of different reflectivity, and a magnetic field to erasethe previously written data.

Pre-recorded optical discs have an advantage of low cost per byte ofrecorded data as long as each byte is the same on each copy of theoptical disc. A disadvantage of pre-recorded optical discs is aninability to add some amount of unique information to each disc afterthe substrate has been manufactured, i.e. serial numbers, productactivation codes, software “patches” or updates, etc.

Recordable optical discs have an advantage in that each disc can haveunique data values recorded on them. A disadvantage of recordableoptical discs is that all of the content data are recorded aftermanufacturing, thereby increasing the costs per byte. Generally, contentsuppliers tend to utilize pre-recorded discs for higher volumeproduction runs where throughput efficiencies can be achieved, but areincreasingly turning to the use of recordable discs for lower volumeproduction runs.

There have been several attempts to create “hybrid” optical discs whereone portion of the disc is pre-recorded and another portion isrecordable. One goal of this approach is to take advantage of low costper byte of pre-recorded data while providing the flexibility to addsubsequent information to the disc. Examples of these types of discsinclude the Kodak® CD-PROM and the ODC™ CDR-ROM. Such discs typicallyhave the pre-recorded portion and the recordable portion manufacturedinto a single surface of the substrate, which complicates the discmanufacturing process and thereby increases the costs per deliveredbyte. Other types of hybrid discs arrange the pre-recorded andrecordable portions so as to be accessed from opposing sides of thedisc, which requires two heads or the disc to be flipped over to accessboth portions.

Due to the continued demand for content provided on optical discs, thereremains a continued need for improved disc formats that are relativelyeasy and inexpensive to implement, and provide flexibility toaccommodate a variety of needs such as tracking and copy protectionsystems. It is to these and other improvements that the presentinvention is generally directed.

SUMMARY OF THE INVENTION

In accordance with preferred embodiments, an optical disc comprises afirst substrate comprising a pre-recorded, first data storage layer anda second substrate comprising a recordable, second data storage layer.The second substrate is affixed to the first substrate such that a datatransducing beam passes through a common exterior boundary surface ofthe disc to access the respective first and second data storage layers.

Preferably, the pre-recorded, first data storage layer comprises asequence of pits and lands formed in said first data storage layer. Dataare preferably recorded to the recordable, second data storage layerusing a writing beam prior to the affixing of the second substrate tothe first substrate.

Moreover, the first data storage layer preferably comprises first datastored in a first range of addressable blocks, the second data storagelayer comprises second data stored in a second range of addressableblocks, and the first and second ranges successively increment over anoverall range of addresses such that a readback system associated withthe data transducing beam interprets the first data and the second dataas being disposed on a common recording layer within said disc. Therespective layers can both extend substantially across the entire radialextent of the disc, or alternatively one of the layers can have areduced size so as to only extend partially across the entire radialextent of the disc.

Preferably, a selected one of the first and second data storage layersstores disc authentication data used to identify said disc as anauthorized copy. Additionally, or alternatively, the recordable layercan be used to store a patch which updates a version of user data storedin the pre-recorded layer.

In accordance with further preferred embodiments, a method is providedcomprising steps of forming a first substrate comprising a pre-recorded,first data storage layer, and affixing a second substrate to the firstsubstrate to form an optical disc. The second substrate comprises arecordable, second data storage layer oriented such that a datatransducing beam subsequently passes through a common boundary surfaceof the disc to access the respective first and second data storagelayers.

The forming step preferably comprises providing a sequence of pits andlands in the first substrate to form the pre-recorded, first datastorage layer, and the method further preferably comprises a step ofusing a writing beam to record data to the recordable, second datastorage layer prior to the affixing step.

As before, addresses associated with the respective layers preferablysuccessively increment over an overall range of addresses such that areadback system interprets the first data and the second data as beingdisposed on a common recording layer within said disc.

The respective layers can both extend substantially across the entireradial extent of the disc, or alternatively one of the layers can have areduced size so as to only extend partially across the entire radialextent of the disc. A selected one of the first and second data storagelayers can be used to store disc authentication data used to identifysaid disc as an authorized copy and can additionally, or alternatively,the recordable layer can be used to store a patch which updates aversion of user data stored in the pre-recorded layer.

In accordance with further preferred embodiments, a method is providedcomprising supplying content data and a specially configured substrateto a replication facility, with the specially configured substratecomprising a pre-recorded data storage layer which stores control dataassociated with the content data. At least one content data substrate isformed at the replication facility, the at least one content datasubstrate comprising a content data storage layer being configured tostore said content data.

Thereafter, the specially configured substrate is affixed to the atleast one content data substrate to form an optical disc, with the discbeing adapted such that the pre-recorded data storage layer and thecontent data storage layer are respectively accessible through a commonexterior boundary surface of the disc by a data transducing beam.

Various other features and advantages of preferred embodiments of thepresent invention will become clear upon a reading of the followingdetailed description in conjunction with the appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 provides a functional block diagram of an optical disc playbacksystem.

FIG. 2 generally illustrates a direction of reading for a single layerdisc.

FIG. 3 generally illustrates a direction of reading for a multi-layerdisc.

FIG. 4 provides a schematic depiction of an optical disc constructed inaccordance with some preferred embodiments of the present invention.

FIG. 5 provides a schematic depiction of an optical disc constructed inaccordance with other preferred embodiments of the present invention.

FIG. 6 depicts a DVD-5 optical disc configuration in accordance with apreferred embodiment.

FIG. 7 depicts a DVD-5 optical disc configuration in accordance withanother preferred embodiment.

FIG. 8 is a DVD-9 optical disc configuration in accordance with anotherpreferred embodiment.

FIG. 9 is a DVD-10 optical disc configuration in accordance with anotherpreferred embodiment.

FIG. 10 shows a DVD-18 optical disc configuration in accordance withanother preferred embodiment.

FIG. 11 illustrates a compact disc (CD) format configuration inaccordance with another preferred embodiment.

FIG. 12 depicts a substrate in conjunction with a molding cavity toillustrate a preferred methodology for forming a selected substrate.

FIG. 13 shows an addressing scheme for a DVD-5 compatible format disc inaccordance with another preferred embodiment.

FIG. 14 shows another addressing scheme for a DVD-5 compatible formatdisc in accordance with another preferred embodiment.

FIG. 15 illustrates another addressing scheme for a DVD-9 compatibleformat disc in accordance with another preferred embodiment.

DETAILED DESCRIPTION

Referring to FIG. 1, shown therein is an optical disc playback system100 configured to read back data stored to an optical disc 102constructed in accordance with various preferred embodiments depictedherein. A motor 104 rotates the disc 102 at a constant linear velocity(CLV) and an optical disc laser pickup assembly comprising a laser basedtransducing head 106 and a linear actuator assembly 108 decodes a datapattern from the disc 102. A readback processor 110 performs therequisite signal processing to output an analog output signal to anoutput device 112. The output device 112 can take a number of formsdepending on the type(s) of data stored on the disc 102 and can thuscomprise a home theater system, a computer system, a portable orautomobile mounted optical disc player, etc.

FIG. 2 generally illustrates the manner in which the disc 102 isaccessed by the system 100 of FIG. 1 during a readback operation. Thedisc 102 is contemplated in FIG. 2 as a single sided, single layer discsuch as a compact disc (CD, CD-ROM, CD-R, CD-R/W, etc.) or certain typesof digital versatile discs (e.g., DVD-5).

A single data layer 114 includes a lead-in area 116 having a table ofcontents (TOC) or other preliminary information relating to the contentsof the disc 102 (in program area 118). A lead-out area 120 indicates theend of the disc 102.

FIG. 3 illustrates the general manner in which the system 100 reads thedisc 102 when the disc has a single side, two layer construction (e.g.,DVD-9). The disc 102 in FIG. 3 includes two data layers 122, 124(denoted as “Layer 0” and “Layer 1”). The first layer 122 (Layer 0) hasa lead-in area 126 followed by a program area 128 and a middle area 130.The second layer 124 (Layer 1) has a middle area 132, a program area 134and a lead-out area 136. During readback, the respective layers are readin the direction shown. The middle areas 130, 132 are typically skipped.The content information (e.g., table of contents) is stored in thelead-in area 106 to identify the contents of both program areas 128,134.

In accordance with preferred embodiments, the optical disc 102 isprovided with a multi-substrate construction such as generallyrepresented by FIGS. 4 and 5. In FIG. 4, a first substrate 150 includesa pre-recorded, first data storage layer 152 (also referred to herein aslayer L0) along a substrate boundary 154. A second substrate 156includes a recordable, second data storage layer 158 (also referred toherein as layer L1) along a substrate boundary 160. Duringmanufacturing, the second substrate 156 is affixed to the firstsubstrate 150 to complete the disc 102 (preferably via an interveninglayer, not shown). The respective data storage layers 152, 158 arethereafter accessed via a data transducing beam (depicted by arrow 161)from the head 106 through a common boundary surface 162 of the disc 102.

The embodiment of FIG. 5 is generally similar to that of FIG. 4, andlike numerals have been used accordingly. However, in FIG. 5 the seconddata storage layer 158 is placed on a top surface 164 of the secondsubstrate. As before, the respective layers 152, 158 are accessedthrough the common boundary surface 162.

Various alternative configurations and features of preferred embodimentsof the present invention are envisioned. In some embodiments, a discauthentication zone is formed from one of the data storage layers 152,158 at a location that is physically beyond the normal access areas(i.e., the lead-in, program and lead-out areas of FIGS. 2 and 3) and isused for disc authentication purposes.

In other embodiments, the disc 102 is configured to allow subsequentupdating by the end user of the recordable layer 158. In yet otherembodiments, addressing schemes are utilized such that the playbacksystem 100 treats the two layers 152, 158 as a “single” recording layerso that, as far as the system is concerned, all of the data in therespective layers 152, 158 are viewed as being in a single layer (i.e.,Layer 0 or Layer 1 of FIG. 3), irrespective of when the data are writtento the recordable layer 158. These and other variations will now bediscussed in turn.

FIG. 6 provides a generalized representation of the optical disc 102 inaccordance with a first embodiment in which the disc is contemplated ascomprising a pre-recorded DVD-5 disc. It will be noted that variousaspect ratios and orientations have been exaggerated to simplify thefollowing discussion.

As those skilled in the art will recognize, a DVD-5 disc is a singlesided, single layer disc that stores about 4.7 gigabytes (G) of data.The disc is approximately 1.2 millimeters (mm) in thickness and formedof two approximately 0.6 mm polycarbonate subdiscs 202, 204 that arebonded together with a thin bonding layer 206.

The top subdisc 202 includes a top substrate boundary 208 and a bottomsubstrate boundary 210. The bottom subdisc 204 includes a top substrateboundary 212 and a bottom substrate boundary 214. A silkscreen orsimilar label 216 is affixed to the top substrate boundary 208 of thetop subdisc 202 to provide human and/or machine (barcode, etc.) readablecontent information.

As mentioned previously, access to the disc 102 in FIG. 6 by the system100 is made upwardly so that the data transducing beam from the opticalpickup passes through the bottom substrate boundary 214 and into thepolycarbonate bottom subdisc 204. The beam impinges upon a metallizedreflective layer 218 formed on the top substrate boundary 212 of thebottom subdisc 204, and the relative reflectivities of the pits andlands formed therein are sensed in relation to a return beam thatreturns back through the bottom subdisc 204 and to the optical pickup.

This type of access is sometimes referred to as “second surfacerecording” since the transducing beam penetrates an outer surface of thedisc 102 (i.e., the lower boundary 214) and passes through the substrateof the disc (i.e., the bottom polycarbonate subdisc 204) to accessanother, opposite surface of the substrate (i.e., the internal boundary212). This is in contrast to “first surface recording” in which thetransducing beam impinges an outer substrate boundary and does notpenetrate the substrate.

The recording layer in the disc 102 in FIG. 6 is referred to as a discauthentication zone (identified at 220) and is also accessed usingsecond surface recording techniques. The zone 220 is preferably formedby a series of wiggle pre-grooves (not shown for simplicity) in the topsubstrate boundary 208 of the top subdisc 202. A recording dye layer 222is overlayed upon the pre-grooves, and a planar metallized reflectivelayer 224 is overlayed upon the recording dye layer 222.

During an access operation to the zone 220, the optical pickup adjuststhe focal length so that the transducing beam passes through boundaries214, 212, 210 and 208 (i.e., through subdiscs 204, 202) to focus uponthe reflective layer 224. Data are selectively written to the recordinglayer 222 either prior to shipment of the disc 102 to the end user, orduring activation of an application program by the end user. The dataserve to identify the contents of the disc 102, provide a key for copyprotection or other authentication purposes, etc.

As desired, the recording layer 222 can additionally or alternatively beconfigured to indicate the number of times that the disc 102 has beenaccessed. For example, an application routine can be configured so thateach time the disc is accessed a digital “tally mark” is recorded to thezone 220. After a predetermined number of allowed accesses (e.g., 5),further access operations are denied.

Alternatively, commercially available, specially formulated dye can beused in the recording layer 222. Such dye degrades under normaltransducing beam exposure. The operation of the disc 102 would beconfigured so that a seek is carried out to the zone 220; after anexcessive number of accesses, the dye would be sufficiently degradedsuch that the seek could not be successfully carried out, and furtheraccess to the disc 102 would be denied.

Thus, while in a preferred embodiment a wiggle pre-groove is formed inthe top boundary surface 208 to enable tracking by a recording system(DVD-R, etc.) during a subsequent writing operation to the zone 220, inan alternative embodiment an actual pit and land pattern is formed inthe top boundary surface 208 so that an existing data set is provided tothe zone, and this data set thereafter becomes inaccessible afterrepeated exposure to the dye layer 222.

FIG. 7 provides an alternative DVD-5 embodiment for the disc 102. Theembodiment in FIG. 7 is similar to that shown in FIG. 6, except that thedisc authentication zone 220 is adjacent the lower boundary 210 of thetop subdisc 202 instead of being adjacent the upper boundary 208 as inFIG. 6. Thus, in this embodiment both the normal recording layer 218 andthe authentication zone 220 are disposed within the composite substrateof the disc 102, albeit on different surfaces at different elevations.It will be understood that this embedded technique can likewise beadapted for the other embodiments presented below.

FIG. 8 shows the disc 102 to generally have a single sided, two layerconfiguration in accordance with the DVD-9 format (with a capacity of8.5 G). Like reference numerals are used for similar features in FIG. 8.The disc 102 in FIG. 8 includes a semi-reflective layer 226 on theboundary 212 of the bottom subdisc 204 and a reflective layer 228 on theboundary 210 of the top subdisc 202. As before, both recording layers226, 228 as well as the authentication zone 220 are accessed from below.

FIG. 9 shows the disc to have a format in accordance with DVD-10 (9.4G), and is a two sided, two layer disc with embedded reflective layers230, 232. The disc must generally be flipped over to allow access to thetop reflective layer 230. The bottom reflective layer 232 and theauthentication zone 220 are both accessed while the disc 102 is orientedas shown in FIG. 9.

FIG. 10 illustrates the disc 102 formatted in accordance with DVD-18(17.1 G), and is a two sided, four layer disc with embedded reflectivelayers 234, 236 and embedded semi-reflective layers 238, 240. Note thatthe transducing beam passes through several interior boundary layersprior to accessing the authentication zone 220, but access otherwisetakes place as discussed above.

While FIGS. 6-10 have represented the disc 102 formatted in accordancewith various DVD formats, such is not limiting. Rather, the disc 102could take any number of existing or future developed formats. Forexample, FIG. 11 illustrates the disc 102 as a conventional CD (0.7 G)with a polycarbonate layer (subdisc) 242 with boundaries 244, 246 and areflective metallized layer 248 on the boundary 246. A protective layer250 with upper substrate boundary 252 is formed on the subdisc 242 asshown, and the authentication zone 220 is formed on the protective layer250. The recording layer 248 and the authentication zone 220 are bothaccessed from below, as before. The CD of FIG. 11 is particularly suitedfor use of a degrading type dye in the recording layer 222 that degradesfrom exposure to a “normal” red CD data transducing laser.

While the foregoing exemplary formats of have been contemplated ascomprising pre-recorded discs, it will be recognized that such is notnecessarily limiting; rather, the various internal recording layers(e.g., 218, 226, 228, 230, 232, 234, 236, 238, 240, 248) couldalternatively be configured to be recordable as desired, and the layer220 could be recordable or pre-recorded. Rendering the layer 220 as aninitially “blank” recordable zone, and then recording data to it beforecompletion of the disc 102 provides the same result (i.e., a“pre-recorded zone”) as if the layer 220 were formed from a metallizedpit and land structure; accordingly, such is viewed as a “pre-recorded”layer for purposes of the appended claims below.

When incorporating the authentication zone into an otherwiseconventional pre-recorded disc, one preferred approach is to providestampers on opposing sides of a molding cavity 270 used in the formationof the replicated discs, as depicted by FIG. 12. A first stamper 272forms a portion of the mold cavity and provides the pattern for theembedded recording layer on a first side of an injection moldedsubstrate 274. A second stamper 276 is disposed on an opposing side ofthe mold cavity 270 to form the wiggle pre-groove (or other features) ona second, opposing side of the substrate 274. Remaining processes arecarried out to complete the replicated discs.

From FIG. 12 it will be noted that the configuration of the mold and thecharacterization of what portion of the disc 102 comprises thegeneralized substrate 274 will depend upon the format of the disc. Forexample, for the DVD-9 format of FIG. 8, the substrate 274 can comprisethe top subdisc 202, since in FIG. 8 the top surface 208 of the topsubdisc 202 receives the wiggle pre-grooves and the bottom surface 210of the top subdisc 202 receives the pit and land sequence to which thereflective layer 226 is adhered. In this case a composite substrate issubsequently formed by the bonding of the bottom subdisc 204 to the topsubdisc 202 during the completion of the disc replication process.

In other cases, the substrate 274 of FIG. 12 can represent a compositeof multiple internal layers that separately formed and subsequentlybonded together, such as the top subdisc 202 and the bottom subdisc 204for the DVD-5 disc in FIGS. 6 and 7. Thus, it will be recognized thatthe molding process represented by FIG. 12 can be viewed as a concurrentor sequential operation, depending upon the requirements of a givenapplication.

FIG. 13 shows the disc 102 in accordance with another preferredembodiment of the present invention referred to herein as the HybridMulti-Layer DVD-5 (HML) disc. In FIG. 13, two substrates 302, 304 areprovided and affixed together using a suitable material (not shown). Thesubstrate 302 includes one data storage layer 306, in this case L0,comprising a sequence of embossed pits and lands 308 and a metallizedlayer 310.

The substrate 304 includes another data storage layer 312, referred toas L1, which has one or more recordable areas (just one area is shown inFIG. 13). The recordable area comprises a wiggle pregroove 314, areflective layer 316 and a dye layer 318. As before, data are written tothe recordable area by selectively exposing the dye layer 318 (whilepositioning the head using the wiggle pregroove 314), thus providing aseries of indelible “stripes” of varying reflectivity to function aspits and lands during readback.

The data storage layer 306 is provided with a first set of addressablesectors, or blocks, which sequentially increment by radius as depictedgraphically by address curve 320. The data storage layer 312 is providedwith a second set of addressable sectors, or blocks, which continue toincrement as shown by curve 320. Thus, addresses on L0 incrementstarting at the lowest address at L0 inner radius and increment to ahigher address at the identified L0 to L1 jump point at 322. Addressescontinue to increment from the L1 jump point to a highest address at L1outer radius. It will be noted that in an alternative embodiment thelayers L0 and L1 can be reversed, as desired so that the data storagelayer 306 is provided on the upper substrate 304 and the data storagelayer 312 is provided on the lower substrate 302.

FIG. 14 provides another alternative embodiment for the HML DVD-5 disc102 which includes more than one jump point. More particularly, in thiscase a first jump point 324 is from pre-recorded layer L1 to recordablelayer L0 and a second jump point 326 is from recordable layer L0 back topre-recorded layer L1. As before, addresses continually increment withradius, regardless of layer.

FIG. 15 provides yet another alternative embodiment for the optical disc102 characterized as an HML DVD-9 disc. In this case, the respective L0and L1 data storage layers 306, 312 substantially extend all the wayacross the radius of the disc 102. As shown graphically by addresscurves 330 and 332, addresses increment across layer 0, jump to layer L1at jump point 328, and increment back across layer L1, with the recordeddata in layer 1 read seamlessly with the prerecorded data on layer 1.

As will be recognized, conventional readback devices typically do notfocus on individual information layers based on absolute thickness orfocal depth, as there can be very large variations in the surfaceflatness of an optical disc, as well as manufacturing tolerances in thethickness of substrates themselves. Instead, readback devices determinewhich layer of a multi-layer disc is currently being read by thecontents of addressing, i.e. some addresses are only present on onelayer and other addresses are only present on a second layer. Thereforethe readback device assumes that when it is reading a given address itis on a certain layer.

Accordingly, a unique property of the HML disc 102 as described hereinis that the two combined layers will contain a set of addresses thatnormally belong to a single information layer. A portion of theaddresses in the set will be contained in the pre-recorded informationon one layer and a portion of the addresses being contained on therecordable or re-writable layer (after recording or re-writing).Generally, this unique addressing scheme will tend to guarantee that theHML disc will be readable by standard multi-layer reading devices suchas DVD-Video and DVD-ROM.

Advantages of HML over conventional single layer hybrid discs includethe fact that standard manufacturing systems and methods can be used tocreate both the pre-recorded information layer and the recordable orre-writable information layer, thereby reducing manufacturing costs.

It is understood that although DVD-5 and DVD-9 are used as examples, theHML technology can be utilized with any number of disc configurations,including existing and future developed formats. Those skilled in theart can readily utilize existing techniques to generate discs inaccordance with the present discussion, and can further readily utilizeexisting writer and readback devices to both record the desired data tothe recordable areas on the discs and readback the prerecorded andrecordable content. Thus, diagrams and further discussion with regard tosuch aspects of the present disclosure are unnecessary for a fullunderstanding of the present discussion.

The DVD-5 examples of FIGS. 13 and 14 utilize parallel track path (PTP)addressing in the respective prerecorded and recordable zones. That is,the direction of reading (from ID to OD) is the same for both zones. TheDVD-9 example from FIG. 15 utilizes opposite track path (OTP)addressing, in that the data from the prerecorded layer 0 are read fromID to OD, and then the data recordable zone in layer 1 are read in theopposite direction (OD to ID). Thus, any number of different readingdirections can be used, including “serpentine” disc configurations wherelayers go “back and forth” among the various layers, depending upon therequirements of a given application.

It will be further noted that the DVD-9 has the recordable data zone inlayer 1 “over” prerecorded data in layer 0, so that the transducingoptical pickup focuses through the semireflective layer in layer 0 toread this zone in layer 1. Thus, while some embodiments have left “gaps”in layer 0 to read the recordable zone in layer 1 (or vice versa), thisis not limiting as evidenced by FIG. 15.

The foregoing various embodiments provide significant flexibility andenhanced processing capabilities in the manufacture of optical discs. Byway of illustration, a content supplier desiring to have a population ofoptical discs manufactured for distribution purposes can take advantageof the various embodiments such as in according with the followingpreferred steps.

First, the content supplier can supply content data and a number ofspecially configured substrates to a replication facility which offersdisc manufacturing and/or replication services. The content data can besupplied via electronic transfer such as by the Internet or byphysically shipping the content data on one or more data storagemediums. The specially configured substrates can be shipped togetherwith the data storage mediums or fabricated elsewhere and forwarded tothe replication facility as directed by the content supplier.

The specially configured substrates preferably have a form such as thetop substrate 156 in FIG. 4, with the associated data storage layer 158storing pre-recorded control data associated with the content data. Thecontrol data can comprise unique serial numbers, product activationcodes, patches to update the control data, etc. as desired. Preferably,if a quantity X of optical discs are desired, then the content suppliercan supply that particular number of specially configured substrates (ormight alternatively supply X+n substrates where n is some small numberof additional substrates to accommodate scrap or other productionrelated issues, etc.).

Second, the replication facility can proceed to form content datasubstrates in a conventional fashion, as represented by the bottomsubstrate 150 in FIG. 4. The content data substrate(s) each have one ormore content data storage layers (e.g., 152, FIG. 4) configured to storethe content data using appropriate encoding techniques. It will be notedthat the content data can be stored as a series of embossed pits andlands, or the content data storage layer(s) can be recordable and thecontent data can subsequently be recorded thereto, as desired.

Third, the replication facility affixes each of the specially configuredsubstrates (e.g., 156) to each corresponding content data substrate(e.g., 150) to form the desired population X of optical discs. Therespective data storage layers are oriented so as to be accessible by adata transducing beam passing through a common exterior boundary surfaceof the discs, such as depicted at 161 in FIG. 4.

In this way, the content supplier can carefully control the total numberof discs created. If extra specially configured substrates are provided,these can be returned or otherwise accounted for. Thus, the variousembodiments presented herein can be utilized to effectively reduce theunauthorized replication of discs. For example, depending on theapplication, the playback system 100 can be readily configured toprevent nonauthorized discs (which do not have the specially configuredlayers) from operating properly.

In a related approach, the content supplier can provide the carefullyenumerated set of substrates as “blanks” of the layers containing therecordable areas to a replication facility with instructions to completethe discs by mastering the embossed data on the layer L0 and then matethe layers L1 and L0.

The disclosed embodiments thus give virtually any existing DVDmanufacturer the ability to create serialized/uniquely identified discson existing equipment, which is a significant advance over the prior artand provides an important, long-desired capability. The recordablelayers can alternatively, or additionally, be used to store software“patches” or updates that are supplied by the content source so that thesame, previously mastered pre-recorded substrate can be mated with“updated” recordable substrates. The recordable layers canalternatively, or additionally, be updated during end user use tocontrol or enhance operation of the content stored in the pre-recordedlayer.

Moreover, because the respective layers are provided on differentboundary surfaces within the disc 102, production issues associated withattempting to provide both pre-recorded and recordable zones on the samesubstrate surface are completely eliminated.

For purposes of the appended claims, the term “pre-recorded” will beconstrued consistent with the foregoing discussion to describe astructure that currently stores selected data. This includes a fixedstructure (such as embossed pits and lands) as well as a recordablestructure that has, in fact, received data recorded thereto. The term“recordable” will be construed consistent with the foregoing discussionto describe a structure adapted to store selected data, and can eitherbe recorded to only once (e.g., a WORM structure) or can be repeatedlyrecorded, erased, and re-recorded (write many structure).

Reference in the appended claims to the orientation of data storagelayers so that such are accessible by a data transducing beam through acommon exterior surface of the disc will be understood consistent withthe foregoing discussion to not require physical inclusion of the beamin the claimed structure, only to describe the structural orientation ofsuch layers. More particularly, such layers are oriented so as to bothbe accessible from the same side of the disc, as compared to anorientation where the beam is applied from opposite sides of the disc inorder to access the layers. It is not required that both layers beactually accessible at the same time; hence, the layers may overlap suchas depicted by FIG. 15, or may be radially exclusive such as depicted inFIGS. 4-14 so that, at some radial positions, one of the layers isaccessible and at other radial positions, the other layer is accessible.

It is to be understood that even though numerous characteristics andadvantages of various embodiments of the present invention have been setforth in the foregoing description, together with details of thestructure and function of various embodiments of the invention, thisdetailed description is illustrative only, and changes may be made indetail, especially in matters of structure and arrangements of partswithin the principles of the present invention to the full extentindicated by the broad general meaning of the terms in which theappended claims are expressed.

1. An optical disc comprising a first substrate comprising apre-recorded, first data storage layer and a second substrate comprisinga recordable, second data storage layer, wherein the second substrate isaffixed to the first substrate to adaptively permit access to therespective first and second data storage layers through a commonexterior boundary surface of the disc by a data transducing beam.
 2. Theoptical disc of claim 1, wherein the pre-recorded, first data storagelayer comprises a sequence of pits and lands formed in said first datastorage layer.
 3. The optical disc of claim 1, wherein data are recordedto the recordable, second data storage layer using a writing beam priorto the affixing of the second substrate to the first substrate.
 4. Theoptical disc of claim 1, wherein the pre-recorded first data storagelayer comprises a recordable portion to which data are recorded using awriting beam prior to the affixing of the second substrate to the firstsubstrate.
 5. The optical disc of claim 1, wherein the first datastorage layer comprises first data stored in a first range ofaddressable blocks, wherein the second data storage layer comprisessecond data stored in a second range of addressable blocks, and whereinthe first and second ranges successively increment over an overall rangeof addresses such that a readback system associated with the datatransducing beam interprets the first data and the second data as beingdisposed on a common recording layer within said disc.
 6. The opticaldisc of claim 1, wherein a selected one of the first and second datastorage layers stores disc authentication data used to identify saiddisc as an authorized copy.
 7. The optical disc of claim 1, wherein aselected one of the first and second substrates further comprises alayer of material having an initial translucency which selectivelychanges in response to subsequent accesses by said data transducing beamso as to ultimately prevent successful access to the associated datastorage layer.
 8. The optical disc of claim 1, wherein the pre-recorded,first data storage layer comprises user data, and wherein therecordable, second data storage layer comprises a data key which, uponsuccessful retrieval of said key using said data transducing beam,permits retrieval of said user data.
 9. The optical disc of claim 1,wherein the pre-recorded, first data storage layer comprises user data,and wherein the recordable, second data storage layer comprises a patchwhich updates a version of said user data.
 10. The optical disc of claim1, wherein the respective first and second data storage layers eachextend substantially across an entire radial extent of the disc.
 11. Theoptical disc of claim 1, wherein a selected one of the first and seconddata storage layers extends substantially across an entire radial extentof the disc, and wherein the remaining one of the first and second datastorage layers has a reduced size so as to extend across substantiallyless than the entire radial extent of the disc.
 12. The optical disc ofclaim 1 characterized as a DVD compatible disc.
 13. The optical disc ofclaim 1 characterized as a CD compatible disc.
 14. A method, comprising:forming a first substrate comprising a pre-recorded, first data storagelayer; and affixing a second substrate to the first substrate to form anoptical disc, the second substrate comprising a recordable, second datastorage layer oriented such that the first and second data storagelayers are respectively accessible by a data transducing beam adapted topass through a common exterior boundary surface of the disc.
 15. Themethod of claim 14, wherein the forming step comprises providing asequence of pits and lands in the first substrate to form thepre-recorded, first data storage layer.
 16. The method of claim 14,further comprising a step of using a writing beam to record data to therecordable, second data storage layer prior to the affixing step. 17.The method of claim 14, wherein the pre-recorded first data storagelayer comprises a recordable portion, and wherein the method furthercomprises using a writing beam to record data to the recordable portionprior to the affixing step.
 18. The method of claim 14, wherein acontent supplier identifies user data to be placed on a selected one ofthe first and second data storage layers, and wherein the method furthercomprises the content supplier providing the user data and the remainingone of the first and second data storage layers to a replicationfacility which carries out at least the attaching step.
 19. The methodof claim 18, wherein the replication facility additionally carries outthe forming step to place the user data on the first data storage layer.20. The method of claim 14, wherein the first data storage layercomprises first data stored in a first range of addressable blocks,wherein the second data storage layer comprises second data stored in asecond range of addressable blocks, and wherein the first and secondranges successively increment over an overall range of addresses suchthat a readback system associated with the data transducing beaminterprets the first data and the second data as being disposed on acommon recording layer within said disc.
 21. The method of claim 14,wherein a selected one of the first and second data storage layersstores disc authentication data used to identify said disc as anauthorized copy.
 22. The method of claim 14, wherein a selected one ofthe first and second substrates further comprises a layer of materialhaving an initial translucency which selectively changes in response tosubsequent accesses by said data transducing beam so as to ultimatelyprevent successful access to the associated data storage layer.
 23. Themethod of claim 14, wherein the pre-recorded, first data storage layercomprises user data, and wherein the recordable, second data storagelayer comprises a data key which, upon successful retrieval of said keyusing said data transducing beam, permits retrieval of said user data.24. The method of claim 14, wherein the pre-recorded, first data storagelayer comprises user data, and wherein the recordable, second datastorage layer comprises a patch which updates a version of said userdata.
 25. The method of claim 14, wherein the respective first andsecond data storage layers each extend substantially across an entireradial extent of the disc.
 26. The method of claim 14, wherein aselected one of the first and second data storage layers extendssubstantially across an entire radial extent of the disc, and whereinthe remaining one of the first and second data storage layers has areduced size so as to extend across substantially less than the entireradial extent of the disc.
 27. The method of claim 14 wherein theoptical disc is characterized as a DVD compatible disc.
 28. The methodof claim 14 wherein the optical disc is characterized as a CD compatibledisc.
 29. An optical disc formed by a process comprising steps of:forming a first substrate comprising a pre-recorded, first data storagelayer; and affixing a second substrate to the first substrate to formthe optical disc, the second substrate comprising a recordable, seconddata storage layer oriented such that the first and second data storagelayers are respectively accessible by a data transducing beam passingthrough a common exterior boundary surface of the disc.
 30. A method,comprising: supplying content data and a specially configured substrateto a replication facility, the specially configured substrate comprisinga pre-recorded data storage layer which stores control data associatedwith the content data; forming at least one content data substrate atthe replication facility, the at least one content data substratecomprising a content data storage layer configured to store said contentdata; and subsequently affixing the specially configured substrate tothe at least one content data substrate to form an optical disc, thedisc adapted such that the pre-recorded data storage layer and thecontent data storage layer are respectively accessible through a commonexterior boundary surface of the disc by a data transducing beam. 31.The method of claim 30, wherein the content data storage layer of theforming step comprises a sequence of embossed pits and lands in the atleast one content data substrate.
 32. The method of claim 30, whereinthe content data storage layer of the forming step comprises arecordable portion, and wherein the method further comprises a step ofrecording the content data to said recordable portion.
 33. The method ofclaim 30, wherein the pre-recorded data storage layer of the speciallyconfigured substrate comprises a recordable portion, and wherein themethod further comprises a step of using a writing beam to record thecontrol data to the recordable portion prior to the supplying, formingand subsequently affixing steps.
 34. The method of claim 30, wherein thecontrol data comprises disc authentication data used to identify saiddisc as an authorized copy.
 35. The method of claim 30, wherein thecontrol data updates a version of the pre-recorded, first data storagelayer comprises user data, and wherein the recordable, second datastorage layer comprises a patch which updates a version of said userdata.
 36. The method of claim 30 wherein the optical disc ischaracterized as a DVD compatible disc.
 37. The method of claim 30wherein the optical disc is characterized as a CD compatible disc.